Writer's Block

Why is it that whenever I have a story, I need a pen? Or, when I have a pen, I need a story? Well, right now, I have the second problem. Writer's block: the worst disease known to writers. I really want to start on another fanfiction, but alas! I have no clue what I'm going to write about. I'm thinking about writing a romance/tragedy, but I can't decide on what pairing(s) I want to use... I may do one about my Ponysona and an OC of mine, but I dunno... I was also wanting to do a pairing with Rarity and another character. I need help! Please, please, please give me some ideas. Anything. NOTHING is worthless. As soon as I find something to go on, I will write like there's no tomorrow (hopefully there will be a tomorrow, what with reports of "the end of the world". Psh, like that'll happen soon). I may not post immediately, but I will post at some point. I'm shooting for the weekends. (Fingers crossed that I can keep this up!) Thanks so much!